Operation -- Annihilate! - Recap

The Enterprise is on a course tracing a 200-year old pattern of mass insanity that has moved across the galaxy, leaving devastated civilizations in its wake. They are heading for the next planet, Deneva, and as they approach Kirk tries to contact a private transmitter without success. They pick up a small scout ship approaching the Denevan sun that’s too far away to snag with a tractor beam. They try to warn the pilot off but he appears to be insane. The Enterprise approaches the sun and try to stop him without success, with their own shields overheating. The pilot suddenly declares that he’s free just as the sun consumes his ship. As they head for Deneva, McCoy realizes that Kirk has a brother Sam who works as a scientist on the planet, and is accompanied by his family.

Kirk and the others go down to the planet but find no natives on the streets. They scan and detect their life signs inside the buildings but there’s no indication they wish to come out. Suddenly a small group of men come after them, alternately screaming at them to leave and wielding their clubs. Finally they attack the landing party, which stuns them into unconsciousness. However, McCoy determines that even stunned, the men are being violently stimulated. Hearing a scream, they investigate and find a sealed laboratory. A woman whom Kirk identifies as his sister-in-law Aurelan is trying to block a damaged air vent but they find no sign of an intruder. They do however, find Kirk’s nephew Peter… and his brother Sam, dead.

They take Aurelan and Peter back to the ship where McCoy determines they’re both in extreme pain to the point where he has to keep them tranquilized. They risk reviving Aurelan who manages to blurt out that eight months ago something came to Deneva on a ship from the preceding planet in the chain of madness. “They” then spread across the planet, taking over everyone and forcing them to build more ships. As she speaks, she suffers from increasing levels of pain until she dies from the shock to her system.

Kirk returns to the planet with the others and they search for the mysterious creatures responsible. Inside a darkened building they finally find the intruders: Frisbee-sized organisms capable of flight and almost immune to phaser fire. Concentrated phaser fire knocks one down and the landing party retreats, but the creature revives and flies onto Spock’s back. They pry it off but Spock has gone into shock. Back on the ship, McCoy determines the creature injected something into Spock. He tries to remove it but discovers that tissue has spread throughout Spock’s nervous system and is impossible to remove with surgery without killing the host body.

A short while later, Spock revives and heads for the bridge, trying to take control of it and bring it down onto the planet. The crew manages to restrain him long enough for Spock to give him a tranquilizer and return him to Sickbay. There, Spock revives and says that as a Vulcan he can fight the pain and is now in control of himself. Kirk is reluctant to allow him back on duty but once left alone, Spock breaks his restraints and goes to the transporter room. He orders Scotty to beam him down but the latter refuses. After a brief struggle, Scotty aims a phaser at Spock and holds him until Kirk and McCoy can arrive. Spock says that the pain is now gone and he’s the logical choice to go to the planet and capture specimen, since he’s already infected. Kirk has no choice but to agree and on the planet, Spock knocks out one human attacker and then stuns and capture one of the creatures.

Back on the Enterprise, Spock determines that the creature is simply a single cell tied to all of the other ones, and they come from some other universe with different properties such as a near-immunity to energy weapons. Since he can’t let the creatures spread to another planet, Kirk has no choice but to find a cure or destroy out everyone infected… including Spock and Peter. They figure that something in the properties of the sun must have destroyed the pilot of the ship, who survived for a few seconds beyond the creature’s destruction. They finally conclude that the high amount of light was the cause and test an equivalent amount on their specimen. They now need to test an infected victim and Spock is again the logical choice. He refuses protective goggles, since none of the Denevans will have any goggles, and is exposed to the light. He reveals that he is cured, but totally blind. They then discover that only high-level invisible light frequencies were necessary, and McCoy acted too soon.

The Enterprise places a series of satellites into orbit around Deneva and then activates them. The resulting light causes the creatures to melt into puddles of goo. Fortunately, Spock regains his eyesight a bit later, explaining that the Vulcans have a second eyelid to protect against their native planet’s sunlight. A relieved McCoy quietly admits to Kirk that he’s relieved they didn’t lose the best first officer in Starfleet… and Spock thanks him, having overheard with his superior hearing.